Ignition plug



A. RUPRECHT.

1611111011 PLUG.

APPLICATION FILED SEPT.18, 1912.

1,412,751.4 Patented 11.11111, 1922.

fry. j.

' ATTY.

YUNITED STATES PATENT OFFICE.

ALBERT RUPRECHT, OF ASPERG, GERMANY.

IGNITION PLUG.

spcification of Letters Patent.

1s,1912. seria1No.72o,954. y n

(GRANTED UNDER THE PROVISIONS OETHE ACT 0F MARCH 31 1921, 41 STAT. L., 1313.)

T 0 all whom t may concern:

Be it known that I, ALBERT RUrnnoHr, a citizen of the German Empire, residing at Asperg, in the Kingdom of Wurttemberg, linpire of Germany, have invented certain new and useful Improvements in Ignition Plugs, of whichthe following is a speciiioation.

In ignition plugs ltorinternal combustion engines, it is usual to make the casing ot the plug oi.E iron or steel` i. e. the part which is screwed into the engine cylinder, and which also covers the insulating sleeve. A disadvantage in this type of plug is that the plug casing is apt to become fixed or bound in the cylinder, due for example to rust, thus malt` ing the loosening or changing of the plug very difficult. In order toV remove this dis` advantage the whole plug` casingL has been iliade of brass or a similar non-corrosive metal, which, however, has the disadvantage that in consequence of the higher co-etlicient of expansion oit' brass compared with iron or steel the plug becomes-loose.v

The obl'ect of the present invention is to remove the abovev mentioned disadvantages the known constructions and to unite thc` advantages of brass, or a similar metal, with those of iron. For that purpose the plug casing according to the inventiomis made ot these two metals, the screw threaded nipple being oi' brass or other non-corrosive metal, thus preventing it being rusted in the cylinder` whereas the head formed as a nut is made ot' iron or steel, so that loosening of the plug cannot occur. In order to get a firm connection between these two parts ot the plug casing composed of different metals, the

screw threaded nipple is provided with sev-y eral saw cuts or slits in its upper edge and is then tightly screwed into the nut in which the insulator has been placed, whereby on the oneV hand the screwed nipple is expanded by the shoulder of the insulator and is tightly connected lwith the nut, and .p on the other hand, the shoulder of the insulator is tightly pressed against a washer inserted between the insulator andthe shoulder of the nut, or

lhead of the plug casing. f

The accompanying, drawing illustrates one form ofthe invention, Figure 1 being a l sectional elevation and Figures 2 and 3 being plans. v

The nut a, or head of the plug casing, according to the invention, is made of iron or steel, whereas the screwed nipple l), by which the plug is secured to the motorcylinder. is made of brass, or a similar metal. The screwed nipple b, is provided with several saw cuts or slits in its upper edge, in order to make it more flexible. It is screwed into the nut or head a, after the usual insulator c, has been placed therein, a washer being placed between the insulator and nut. The shoulder on the 4insulator c, on the one hand slightly -expands the upper saw cut edge of the screwed nipple l), and presses it tightly in the thread of the nut a, and on the other hand, it compresses the washer d, tightly between itself and a shoulder on the nut a. As usual the electrode e, is passed through the insulator c, and is fastened by means of a nut g, a spring washer f, being provided. A nut it, secures the conductor.

' I claim:

In an ignition plug, in combination, a casing comprising a head portion of iron and a nipple of non-corrosive metal. said head portion being provided with an inwardly extending shoulder at its upper end and having its lower part externally threaded. said ninple being externally threaded and having its upper end engaging thethreaded portion ot said head portion, the upper end ot said nipple being slitted, an electrode supporting insulator supported by said casing, said insulator being provided with a shoulder adapted to engage the upper slitted end ol said nipple whereby the upper portion oi said nipple willbe expanded and forced into the threaded portion of said head portion, said insulator being provided with a second shoulder registering with the shoulder on said head portion. and a washer interposed between said last mentioned shoulder'.

In testimony wh'ereot I aliix my si gnature in presence of two witnesses.

ALBERT RUPREoI-ri.

vWitnesses y v RUDOLF WAL'rERs,

` PRIDE KLAIBER.

Patented Apr. 11, 1922. 

